I. Definitions
As used herein, the phrases “III-N,” “III-nitride,” “III-nitride material” and similar terms refer to a compound semiconductor that includes nitrogen and at least one group III element including aluminum (Al), gallium (Ga), indium (In), and boron (B), and including but not limited to any of its alloys, such as aluminum gallium nitride (AlxGa(1-x)N), indium gallium nitride (InyGa(1-y)N), aluminum indium gallium nitride (AlxInyGa(1-x-y)N), gallium arsenide phosphide nitride (GaAsaPb N(1-a-b)), aluminum indium gallium arsenide phosphide nitride (AlxInyGa(1-x-y)AsaPb N(1-a-b)), for example. III-nitride material also refers generally to any polarity including but not limited to Ga-polar, N-polar, semi-polar or non-polar crystal orientations. III-nitride material may also include Wurtzitic, Zincblende or mixed polytypes, and single-crystal, monocrystalline, polycrystalline, or amorphous structures.
II. Background Art
III-nitride material can be formed, for example, by growing the III-nitride material with growth techniques that utilize a carrier gas to transport precursors to a reaction chamber. A carrier gas with a P type dopant can be supplied to the III-nitride material. The III-Nitride material typically retains impurities from the carrier gas that can act as acceptors and form residual complexes with the P type dopants provided by the carrier gas. The residual complexes may be electrically inert thereby neutralizing the P type dopant and interfering with formation of a P type III-nitride material.
The P type dopant can be activated by, for example, using a thermal anneal to break the residual complexes and free the carrier gas impurities. The III-nitride material may have been encapsulated or passivated by an overlying material so that the thermal anneal can be performed at a higher temperature without causing decomposition at the surface of the III-nitride material. When there is encapsulation or passivation, the freed carrier gas impurities typically cannot diffuse through the overlying encapsulating or passivating material and remains trapped at the surface of the III-Nitride material where it can recombine with the P type dopant thereby reforming residual complexes.